bit.addEventListener("click",function () {
    var user = document.getElementById("user");
    var pwd = document.getElementById("pwd");
    if (user.value ==="admin" && pwd.value ==="123") {
        alert("登录成功");
        window.location.href="http://47.116.207.219/homePage";
    } else {
        pwd.value="";
        alert("账号或密码错误")
        }
    })